Apparatus for additive manufacturing of three-dimensional articles

ABSTRACT

A method for forming at least one three-dimensional article through successive fusion of parts of a powder bed, which parts correspond to successive cross sections of the three-dimensional article, the method comprising the steps of: providing a model of the at least one three-dimensional article; applying a first powder layer on a work table; directing a first energy beam from a first energy beam source over the work table causing the first powder layer to fuse in first selected locations according to corresponding models to form a first cross section of the three-dimensional article, where the first energy beam is fusing at least a first region of a first cross section with parallel scan lines in a first direction; varying a distance between two adjacent scan lines, which are used for fusing the powder layer, as a function of a mean length of the two adjacent scan lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a United States divisional patent application andclaims priority to and the benefit of U.S. Nonprovisional patentapplication Ser. No. 14/621,209, filed Feb. 12, 2015, which applicationfurther claims priority to and the benefit of U.S. Provisional PatentApplication Ser. No. 61/949,585, filed Mar. 7, 2014, the content of bothof which as are hereby incorporated by reference in their entirety.

BACKGROUND Related Field

Various embodiments of the present invention relate to an apparatus andmethod for additive manufacturing of three-dimensional articles.

Description of Related Art

Freeform fabrication or additive manufacturing is a method for formingthree-dimensional articles through successive fusion of chosen parts ofpowder layers applied to a worktable. A method and apparatus accordingto this technique is disclosed in US 2009/0152771.

Such an apparatus may comprise a work table on which thethree-dimensional article is to be formed, a powder dispenser, arrangedto lay down a thin layer of powder on the work table for the formationof a powder bed, a ray gun for delivering energy to the powder wherebyfusion of the powder takes place, elements for control of the ray givenoff by the ray gun over the powder bed for the formation of a crosssection of the three-dimensional article through fusion of parts of thepowder bed, and a controlling computer, in which information is storedconcerning consecutive cross sections of the three-dimensional article.A three-dimensional article is formed through consecutive fusions ofconsecutively formed cross sections of powder layers, successively laiddown by the powder dispenser. Further details regarding the controllingcomputer, which may be utilized in certain embodiments to in part or inwhole implement the method described herein may be found in the detaileddescription provided herein.

There is a tendency when fusing a cross section of the three dimensionalarticle with small dimensions, i.e., when using a shorter scan linelength than a predetermined value, that material characteristics isworse compared to cross sections of the same three dimensional articlewith larger dimensions, i.e., when using a longer scan line length thanthe predetermined value. The degraded material characteristics for thesmall dimensions may be caused by porosities and/or incomplete fusion inthe material.

BRIEF SUMMARY

An object of the various embodiments of the present invention is toprovide a method which enables production of a three-dimensional articleby freeform fabrication or additive manufacturing without introducingporosities and/or incomplete fusion when fusing small dimensions, i.e.,using a shorter scan line length than a predetermined value.

The abovementioned article is achieved by the features in the methodaccording to the broadest method-based claims provided herein.

In a first aspect of the invention it is provided a method for formingat least one three-dimensional article through successive fusion ofparts of a powder bed, which parts correspond to successive crosssections of the three-dimensional article, the method comprising thesteps of: providing a model of the at least one three-dimensionalarticle; applying a first powder layer on a work table; directing afirst energy beam from a first energy beam source over the work tablecausing the first powder layer to fuse in first selected locationsaccording to corresponding models to form a first cross section of thethree-dimensional article, where the first energy beam is fusing atleast a first region of a first cross section with parallel scan linesin a first direction; varying a distance between two adjacent scanlines, which are used for fusing the powder layer, as a function of alength of at least one of the two adjacent scan lines.

The advantage of the various embodiments of the present invention isthat any porosity and/or incomplete fusion in the fused material may beeliminated by setting the distance between adjacent scan lines to apredetermined distance range depending on the length of at least one ofthe adjacent scan lines. Since the length of a scan line may vary withthe shape of the object to be fused and/or the scan direction withrespect to the object, the distance between a first pair of adjacentscan lines may be different compared to a second pair of adjacent scanlines, where the first and second pair of adjacent scan lines areadjacent to each other. In a cross section of a three-dimensional objectto be fused with a continuously varying shape, such as a triangle withequal length of its sides, the distance between adjacent scan lines maybe different for each adjacent pair of scan lines along at least aportion of the triangle if the scan direction is parallel to one of itssides.

In an example embodiment of the present invention the distance is also afunction of the sequence of the adjacent scan lines. A non-limitingadvantage of at least this embodiment is that one may vary theseparation distance between two adjacent scan lines depending on when intime they have been provided onto the powder layer for fusing the powderlayer. This may have the advantage of speeding up the time it takes toreach an equilibrium fusion temperature.

In still another example embodiment of the present invention a first twoadjacent scan lines are separated with a first distance and a second twoadjacent scan lines, provided later than the first adjacent scan lines,are separated with a second distance, wherein the first distance issmaller than the second distance. A non-limiting advantage of at leastthis embodiment is that a first two adjacent scan lines are closer toeach other than a second two adjacent scan lines if the first twoadjacent scan lines are provided earlier than the second two adjacentscan lines. The first two adjacent scan lines may be provided at anyplace on a particular cross section of the three-dimensional article.

In an example embodiment of the present invention the distance betweentwo adjacent scan lines is increasing for an increasing length of atleast one of the adjacent scan lines. A non-limiting advantage of atleast this embodiment is that for various dimensions for thethree-dimensional article to be produced the distance between adjacentscan lines may be set to increase for increased dimensions, i.e.,increased scan lengths.

In an example embodiment of the present invention the distance isdetermined as one of a group of: a function of the mean length of thetwo adjacent scan lines, a function of the longest of the two adjacentscan lines, or a function of the shortest of the two adjacent scanlines. A non-limiting advantage of at least this embodiment is that anyone or a combination of the examples given above may be chosen fordetermining the distance between two adjacent scan lines. In analternative embodiment the length of scan lines may be stored beforehandin a look-up table, where each length is corresponding to a specificdistance between adjacent scan lines.

In another example embodiment the distance between adjacent scan linesis constant if one or both of the adjacent scan lines is longer than apredetermined value.

For scan lengths above a predetermined value the distance betweenadjacent scan lines may be kept constant without affecting the finalmaterial properties. However, for scan lengths shorter than thepredetermined value the distance between adjacent scan lines needs to bevaried as a function of the scan length in order to maintain the finalmaterial properties. The distance between adjacent scan lines may bedecreased for decreased scan lengths, i.e., the shorter the mean scanlength of two adjacent scan lines the smaller the distance between theadjacent scan lines. This may apply only for scan line lengths shorterthan the predetermined value.

In still another example embodiment the distance between two adjacentscan lines is varied linearly as a function of the mean length of thetwo adjacent scan lines up to the predetermined value or as a functionof the shortest scan line length of the two adjacent scan lines up tothe predetermined value. Alternatively the distance may also be variednon-linearly as a function of the mean length or shortest scan line ofthe two adjacent scan lines. For instance a function according toY=A+BX+CX² may be used, where A, B and C are constants, Y=distancebetween the adjacent scan lines, X=mean scan line length or shortestscan line length of the two adjacent scan lines.

In still another example embodiment the method further comprises thestep of keeping a scan speed and/or an energy beam power and/or anenergy beam spot size on the powder layer constant at least for the twoadjacent scan lines. A non-limiting advantage of at least thisembodiment is that only the distance between adjacent scan lines isvaried when melting a particular region of a cross section foreliminating porosity in the final three-dimensional article. In anexample embodiment the scan speed and/or energy beam power and/or energybeam spot size on the powder layer is constant for the full crosssection of the three-dimensional article.

In still another example embodiment the method further comprising thestep of keeping a time sink plus a first scan line time constant foreach scan line in at least one cross section of the three-dimensionalarticle. A non-limiting advantage of at least this embodiment is thatthe control and predictability of the material properties, such astensile strength, ductility and/or microstructure may still further beimproved. The time sink is the idling time where no fusing of the powdertakes place or where fusing of the powder takes place elsewhere inrelation to the first scan line.

In still another example embodiment of the present invention the energybeam is at least one of an electron beam or a laser beam.

At least one advantage of the various embodiments of the presentinvention is that it may be equally applicable to a laser based additivemanufacturing process as an electron beam based additive manufacturingprocess.

In still another example embodiment the scan lines in at least one layerof at least one three-dimensional article may be straight lines. Instill another example embodiment the scan lines in at least one layer ofat least one three-dimensional region are meandering. The advantage ofthese embodiments of the present invention is that the inventive conceptmay be equally applicable irrespective of the type of scan lines used,i.e., they may be straight lines, meandering lines, saw-tooth shapedlines or any other shapes of the scan lines.

In yet another example embodiment of the present invention the adjacentscan lines in at least a first region may be fused with a first energybeam from a first energy beam source and a second energy beam from asecond energy beam source. A non-limiting advantage of at least thisembodiment is that the manufacturing speed may be increased my usingmultiple energy beam sources which may be set to provide scan lines onthe powder surface having a distance between adjacent scan lines relatedto the length of at least one of the adjacent scan lines emanated eitherfrom the first or the second energy beam source.

In yet another example embodiment of the present invention the firstenergy beam is emanating from a first electron beam source and thesecond energy beam is emanating from a first laser beam source. In stillanother example embodiment the first energy beam is emanating from afirst electron beam source and the second energy beam is emanating froma second electron beam source. In yet another example embodiment thefirst energy beam is emanating from a first laser beam source and thesecond energy beam is emanating from a second laser beam source.

A non-limiting advantage of at least these and still other embodimentsis that different types of energy beam sources or equal types of energybeam source may be used to provide the scan lines on the powder surface.A laser beam may be used for regions with shorter scan lengths and anelectron beam may be used for regions with longer scan lines fordecreasing the manufacturing time and/or tailor the material properties.

In still another example embodiment the first and second energy beamsare fusing the adjacent scan lines simultaneously. A non-limitingadvantage of at least this embodiment is that manufacturing time maystill be reduced. In an example embodiment two adjacent scan lines maybe fused simultaneously with energy beam from two energy beam sources,where the energy beam sources may be of the same type or differenttypes.

In still another example embodiment, a program element is provided thatis configured and arranged to, when executed on a computer, implement amethod forming at least one three-dimensional article through successivefusion of parts of a powder bed, which parts correspond to successivecross sections of the three-dimensional article. The method in this andother embodiments comprises at least the steps of: applying a firstpowder layer on a work table; directing a first energy beam from a firstenergy beam source over the work table so as to cause the first powderlayer to fuse in first selected locations according to a correspondingmodel of the at least one three-dimensional article so as to form afirst cross section of the three-dimensional article, where the firstenergy beam is configured to fuse at least a first region of a firstcross section with two or more parallel scan lines in a first direction;and determining a distance between two adjacent of the two or moreparallel scan lines, which are used for fusing the powder layer, as afunction of a length of at least one of the two adjacent scan lines.

In still another embodiment, a non-transitory computer program productcomprising at least one non-transitory computer-readable storage mediumhaving computer-readable program code portions embodied therein isprovided. The computer-readable program code portions therein compriseat least: an executable portion configured for directing application ofa first powder layer on a work table; an executable portion configuredfor directing a first energy beam from a first energy beam source overthe work table so as to cause the first powder layer to fuse in firstselected locations according to a corresponding model of the at leastone three-dimensional article so as to form a first cross section of thethree-dimensional article, where the first energy beam is configured tofuse at least a first region of a first cross section with two or moreparallel scan lines in a first direction; and an executable portionconfigured for determining a distance between two adjacent of the two ormore parallel scan lines, which are used for fusing the powder layer, asa function of a length of at least one of the two adjacent scan lines.

In still another embodiment, an apparatus is provided for forming atleast one three-dimensional article through successive fusion of partsof a powder bed, which parts correspond to successive cross sections ofthe three-dimensional article. In these and other embodiments, theapparatus comprises: a control unit having stored thereon a computermodel of the at least one three-dimensional article; and at least oneenergy beam from at least one energy beam source, the at least oneenergy beam source being at least one of an electron beam or a laserbeam. The at least one energy beam is configured to be directed, via thecontrol unit, over a first powder layer applied on a work table so as tocause the first powder layer to fuse in first selected locationsaccording to the computer model. In these and other embodiments, the atleast one energy beam is configured to form a first cross section of thethree-dimensional article. The further, the at least one energy beam isconfigured to fuse at least a first region of the first cross sectionwith two or more parallel scan lines extending in a first direction.Additionally, the control unit is configured to determine a distancebetween two adjacent of the two or more parallel scan lines as afunction of a length of at least one of the two adjacent scan lines.

In still another embodiment, a computer-implemented method for formingat least one three-dimensional article through successive fusion ofparts of a powder bed, which parts correspond to successive crosssections of the three-dimensional article, is provided. Thecomputer-implemented method comprises the steps of: receiving andstoring, within one or more memory storage areas, a model of the atleast one three-dimensional article; applying, based at least in partupon the model, a first powder layer on a work table; directing, via atleast one computer processor, a first energy beam from a first energybeam source over the work table so as to cause the first powder layer tofuse in first selected locations according to the model and so as toform a first cross section of the three-dimensional article, where thefirst energy beam is configured to fuse at least a first region of afirst cross section with two or more parallel scan lines in a firstdirection; and determining, via the at least one computer processor, adistance between two adjacent of the two or more parallel scan lines,which are used for fusing the powder layer, as a function of a length ofat least one of the two adjacent scan lines.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 depicts a view from above of a three-dimensional article providedwith a pattern of scan lines according to various embodiments of thepresent invention;

FIG. 2 illustrates schematically a view from above of an exampleembodiment of a melting strategy of a three-dimensional article usingtwo energy beams according to various embodiments of the presentinvention,

FIG. 3 depicts an apparatus in which various embodiments of the presentinvention may be implemented;

FIG. 4 depicts graph of a distance between adjacent scan lines as afunction of scan length,

FIG. 5 depicts a schematic flow chart of the inventive method;

FIG. 6 illustrates schematically a view from above of another exampleembodiment of a melting strategy of a three-dimensional article usingtwo energy beams according to the present invention;

FIG. 7 is a block diagram of an exemplary system 1020 according tovarious embodiments;

FIG. 8A is a schematic block diagram of a server 1200 according tovarious embodiments; and

FIG. 8B is a schematic block diagram of an exemplary mobile device 1300according to various embodiments.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various embodiments of the present invention will now be described morefully hereinafter with reference to the accompanying drawings, in whichsome, but not all embodiments of the invention are shown. Indeed,embodiments of the invention may be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure willsatisfy applicable legal requirements. Unless otherwise defined, alltechnical and scientific terms used herein have the same meaning ascommonly known and understood by one of ordinary skill in the art towhich the invention relates. The term “or” is used herein in both thealternative and conjunctive sense, unless otherwise indicated. Likenumbers refer to like elements throughout.

Still further, to facilitate the understanding of this invention, anumber of terms are defined below. Terms defined herein have meanings ascommonly understood by a person of ordinary skill in the areas relevantto the present invention. Terms such as “a”, “an” and “the” are notintended to refer to only a singular entity, but include the generalclass of which a specific example may be used for illustration. Theterminology herein is used to describe specific embodiments of theinvention, but their usage does not delimit the invention, except asoutlined in the claims.

The term “three-dimensional structures” and the like as used hereinrefer generally to intended or actually fabricated three-dimensionalconfigurations (e.g., of structural material or materials) that areintended to be used for a particular purpose. Such structures, etc. may,for example, be designed with the aid of a three-dimensional CAD system.

The term “electron beam” as used herein in various embodiments refers toany charged particle beam. The sources of charged particle beam caninclude an electron gun, a linear accelerator and so on.

FIG. 3 depicts an example embodiment of a freeform fabrication oradditive manufacturing apparatus 300 according to prior art in whichvarious embodiments of the present invention may be implemented. Theapparatus 300 comprises an electron beam source 306; two powder hoppers304, 314; a start plate 316; a build tank 310; a powder distributor 328;a build platform 302; a vacuum chamber 320, a beam deflection unit 307and a control unit 308. FIG. 3 discloses only one electron beam sourcefor sake of simplicity. Of course, any number of electron beam sourcesmay be used.

The vacuum chamber 320 is capable of maintaining a vacuum environment bymeans of or via a vacuum system, which system may comprise aturbomolecular pump, a scroll pump, an ion pump and one or more valveswhich are well known to a skilled person in the art and therefore needno further explanation in this context. The vacuum system may becontrolled by the control unit 308. If using another beam source than anelectron beam source, the build tank may be provided in an enclosablechamber provided with ambient air or a suitable gas atmosphere at orbelow atmosphere pressure. In still another example embodiment the buildchamber may be provided in open air.

The electron beam source 306 is generating an electron beam, which maybe used for melting or fusing together powder material 305 provided onthe work table. The electron beam source 306 may be provided in thevacuum chamber 320. The control unit 308 may be used for controlling andmanaging the electron beam emitted from the electron beam source 306.The electron beam 351 may be deflected between at least a first extremeposition 351 a and at least a second extreme position 351 b.

At least one focusing coil, at least one deflection coil and an electronbeam power supply may be electrically connected to the control unit 308.The beam deflection unit 307 may comprise the at least one focusingcoil, the at least one deflection coil and optionally at least oneastigmatism coil. In an example embodiment of the invention the electronbeam source may generate a focusable electron beam with an acceleratingvoltage of about 60 kV and with a beam power in the range of 0-3 kW. Thepressure in the vacuum chamber may be in the range of 1×10⁻³-1×10⁻⁶ mBarwhen building the three-dimensional article by fusing the powder layerby layer with the energy beam source 306.

Instead of melting the powder material with an electron beam, one ormore laser beams and/or electron beams may be used. Each laser beam maynormally be deflected by one or more movable mirror provided in thelaser beam path between the laser beam source and the work table ontowhich the powder material is arranged which is to be fused by the laserbeam. The control unit 308 may manage the deflection of the mirrors soas to steer the laser beam to a predetermined position on the worktable.

The powder hoppers 304, 314 may comprise the powder material to beprovided on the start plate 316 in the build tank 310. The powdermaterial may for instance be pure metals or metal alloys such astitanium, titanium alloys, aluminum, aluminum alloys, stainless steel,Co—Cr—W alloy, etc. Instead of two powder hoppers, one powder hopper maybe used. Other designs and/or mechanism for of the powder supply may beused, for instance a powder tank with a height-adjustable floor, i.e.,providing powder from below instead of as in FIG. 3 where the powder isfed from above.

The powder distributor 328 may be arranged to lay down a thin layer ofthe powder material on the start plate 316. During a work cycle thebuild platform 302 will be lowered successively in relation to theenergy beam source after having fused the layer of powder material. Inorder to make this movement possible, the build platform 302 is in oneembodiment of the invention arranged movably in vertical direction,i.e., in the direction indicated by arrow P. This means that the buildplatform 302 may start in an initial position, in which a first powdermaterial layer of necessary thickness has been laid down on the startplate 316. A first layer of powder material may be thicker than theother applied layers. The reason for starting with a first layer whichis thicker than the other layers is that one may not want a melt-throughof the first layer onto the start plate. The build platform maythereafter be lowered in connection with laying down a new powdermaterial layer for the formation of a new cross section of athree-dimensional article. Means for lowering the build platform 302 mayfor instance be through a servo engine equipped with a gear, adjustingscrews etc.

In FIG. 5 it is depicted a flow chart of an example embodiment of amethod according to the present invention for forming at least onethree-dimensional article through successive fusion of parts of a powderbed, which parts correspond to successive cross sections of thethree-dimensional article. The method comprising a first step 510 ofproviding a model of the at least one three dimensional article. Themodel may be a computer model generated via a CAD (Computer AidedDesign) tool. When building more than one three-dimensional article thearticles may be equal or different to each other.

In a second step 520 a first powder layer is provided on a work table.The work table may be the start plate 316, the build platform 302, apowder bed or a partially fused powder bed. The powder may bedistributed evenly over the worktable according to several methods. Oneway to distribute the powder is to collect material fallen down from thehopper 304, 314 by a rake system. The rake or powder distributor 328 maybe moved over the build tank 310 and thereby distributing the powderover the work table.

A distance between a lower part of the rake and the upper part of thestart plate or previous powder layer determines the thickness of powderdistributed over the work table. The powder layer thickness can easilybe adjusted by adjusting the height of the build platform 302.

In a third step 530 a first energy beam is directed from a first energybeam source over the work table causing the first powder layer to fusein first selected locations according to corresponding models to form afirst cross section of the at least one three-dimensional article 303.

The first energy beam may be fusing at least a first region of a firstcross section with parallel scan lines in a first direction.

The first energy beam may be an electron beam or a laser beam. The beamis directed over the work table from instructions given by the controlunit 308. In the control unit 308 instructions for how to control thebeam source 306 for each layer of the three-dimensional article may bestored.

In a fourth step 540 a distance between two adjacent scan lines isdetermined, which are used for fusing the powder layer, as a function ofa length of at least one of the two adjacent scan lines.

FIG. 1 depicts a view from above of a powder layer of athree-dimensional article 100. The powder layer has been provided with apattern of scan lines according to an example embodiment of the presentinvention. The pattern of scan line may be determined during themanufacture of the three-dimensional article 100 or partly or completelybefore starting the manufacture of the three-dimensional article 100.The three-dimensional article 100 in FIG. 1 is tapered. A top sectionhas a width B₁ and a length L, a middle section has a width B₂ and alength L and a bottom section has a width B₃ and a length L, whereB₁>B₂>B₃. The direction of scan lines in this embodiment is chosen to beorthogonal to the length L of the sections of the three-dimensionalarticle 100 for clarity reasons. However, the direction of scan linesmay be at any angle in relation to the length L of the sections. In anexample embodiment the direction of scan lines may be altered from onelayer to another by a predetermined angle.

The scan lines in the top section have a length B₁. The distance betweenadjacent scan lines in the top section is D₁. The scan lines in themiddle section have a length B₂. The distance between adjacent scanlines in the middle section is D₂. The scan lines in the bottom sectionhave a length B₃. The distance between adjacent scan lines in the bottomsection is D₃. According to various embodiments of the invention the adistance between two adjacent scan lines, which are used for fusing thepowder layer, may be determined as a function of a length of at leastone of the two adjacent scan lines, i.e., the distance D₁, D₂, D₃between adjacent scan lines is related in some predetermined way to thecorresponding length B₁, B₂, B₃ of at least one of the adjacent scanlines. In FIG. 1 B₁>B₂>B₃ and D₁>D₂>D₃, meaning that the distancebetween two adjacent scan lines D₁, D₂, D₃ is increasing for increasinglength B₁, B₂, B₃ of at least one of the adjacent scan lines.

In an example embodiment the distance D₁, D₂, D₃ may be determined asone of a group of: a function of the mean length of the two adjacentscan lines, a function of the longest of the two adjacent scan lines, ora function of the shortest of the two adjacent scan lines. In an exampleembodiment the function may be a linear function, Y=A+Bx, where Y is thedistance between adjacent scan lines, X is the length of one of theadjacent scan lines and A and B are constants. In another exampleembodiment the function may be a polynomial function, Y=A+Bx+CX2, whereY is the distance between adjacent scan lines, X is the length of one ofthe adjacent scan lines and A, B and C are constants. Alternatively anyother suitable function may be used such as an exponential function orlogarithmic function etc.

FIG. 4 depicts an example embodiment of a diagram of the distancebetween adjacent scan lines as a function of at least one of theadjacent scan line lengths. From FIG. 4 one can see that for scan linelengths longer than 8 mm the distance between adjacent scan lines isconstant. However, for scan line lengths shorter than 8 mm the distancebetween adjacent scan lines is shorter for shorter scan line lengths,i.e., the derivative of the slanted line between 0-8 mm scan line lengthis positive.

The scan length in FIG. 4 may be one of the adjacent scan line lengths(the shortest or the longest), the mean value of adjacent scan lines,the sum of adjacent scan lines, the product of the scan lines or anyother mathematical function of one or both of the adjacent scan lines.

In an example embodiment the distance may start to become shorter for asecond predetermined scan length. For instance in FIG. 4, the distancebetween adjacent scan lines may start to become shorter again if thescan length is longer than 20 mm.

In another example embodiment a scan speed and/or an energy beam powerand/or an energy beam spot size on the powder layer may be kept constantfor the two adjacent scan lines. This means that only one parameter maybe changed during the fusion process of the powder layer. The parameterto be changed along a scan line may be the spot size or the beam poweror the scan speed. In another example embodiment two parameters may bechanged along a scan line, for instance the beam power and the spotsize; the beam power and the scan speed; or the scan speed and the spotsize.

In yet another example embodiment a time sink plus a scan line time maybe kept constant for each scan line in at least one cross section of thethree-dimensional article. This means that the total time of the timesink plus the scan line time for the scan lines in the top section takesequally long as the time sink plus the scan line time for the scan linesin the middle section. The scan line time plus the time sink for thescan lines in the middle section takes equally long as the time sinkplus the scan line time for the scan lines in the bottom section. Theadvantage of keeping the scan line time plus a time sink constant foreach scan line independently of the scan line length is that thematerial properties may be improved, such as the control of themicrostructure in the three-dimensional article. The time sink isconsidered to be the time when the energy beam is not fusing a powdermaterial at all or when the energy beam is fusing powder material atanother position, i.e., a second scan line.

The energy beam may be a laser beam or an electron beam. The laser beamspot or electron beam spot may fuse the powder material in straightlines or meandering lines or any other suitable form of the scan linessuch as saw tooth shaped.

In an example embodiment a first scan line of a first pair of adjacentscan lines in at least a first region is fused with a first energy beamfrom a first energy beam source and a second scan line of the first pairof adjacent scan lines in at least the first region is fused with asecond energy beam from a second energy beam source.

In another example embodiment a first pair of adjacent scan lines in atleast a first region are fused with a first energy beam from a firstenergy beam source and a second pair of adjacent scan lines in at leasta second region are fused with an energy beam from a second energy beamsource.

FIG. 2 illustrates schematically a view from above of athree-dimensional article 200 fused with a first energy beam 210 from afirst energy beam source (not shown) and a second energy beam 220 from asecond energy beam source (not shown). The three dimensional article 200has the same dimension as the three-dimensional article 100 in FIG. 1,so the distance between scan lines in the different section (top, middleand bottom) may be the same. The first energy beam 210 is in FIG. 2producing a scan line 215 in the bottom section of the three-dimensionalarticle 200. The second energy beam 220 is in FIG. 2 producing a scanline 225 in the bottom section of the three-dimensional article 200. InFIG. 2 the scan line 225 which is to be finalized and the alreadyfinalized scan line above are fused with the second energy beam from thesecond energy beam source, i.e., two adjacent scan lines are emanatingfrom the second energy beam source. In FIG. 2 the scan line 215 which isto be finalized and the already finalized scan lines below are fusedwith first energy beam from the first energy beam source, i.e., twoadjacent scan lines are emanating from the first energy beam source.

Alternatively every second scan line may be applied on thethree-dimensional article 200 from the first energy beam source and theother scan liens from the second energy beam source. The first endsecond energy beam sources may produce scan lines on thethree-dimensional article simultaneously, i.e., they may produce scanlines adjacent to each other or scan lines separated with a sufficientdistance in order to produce later on a scan line in between them. Instill another example embodiment a single scan line may have a first endsecond portion. The first portion may be produced by the first energybeam and the second portion with the second beam. The first and secondportions may be overlapping or stitched together without overlap.

The distance between adjacent scan lines in the top section in largerthan the distance between adjacent scan lines in the bottom section.This has to do with, as has been explained before, that the scan linelength in the top section is longer than the scan line length in thebottom section. For dimensions see the discussion in relation to thethree-dimensional article 100 in FIG. 1 which is a cop of thethree-dimensional article 200 in FIG. 2.

In an example embodiment the first energy beam source may be a lasersource and the second energy beam source may be a electron beam source.In another example embodiment the first energy beam source may be afirst laser source and the second energy beam source may be a secondlaser source. The first and second laser source may be identical. Thefirst laser source may have a different maximum power output than thesecond laser source. The first end second laser source may differ inother parameters such as the way the laser is produced.

In still another example embodiment the first energy beam source may bea first electron beam source and the second energy beam source may be asecond electron beam source. The first and second electron beam sourcesmay be identical. The first electron beam source may have a differentmaximum power output than the second electron beam source. Sid firstelectron beam source may differ in other parameters such as the way theelectron beam is generated, heated cathode or from a plasma.

If multiple three-dimensional articles are produced simultaneously thescan lines in a first article may be in a first direction and scan linesin a second article may be in a second direction. In FIGS. 1 and 2 thescan lines are illustrated to be in one and the same direction, i.e.,horizontal. However, different directions of scan lines may be used fordifferent articles and or layers of a specific article.

Two consecutive scan lines for a single article and single layer may beseparated by a predetermined time interval. The more the scan speed isincreased the more articles may be scanned within the predetermined timeinterval. An upper limit of the scan speed may be the power of theenergy beam source. In order to melt a specific material a specificenergy deposition into the material is required. When increasing thescan speed for a given energy beam spot size, the power of the energybeam is required to increase in order to deposit the same amount ofenergy into the material. At a certain scan speed a maximum power levelof the energy beam source may be reached, i.e., the scan speed may notbe increased any more without decreasing the energy deposit into thematerial.

In an example embodiment of the present invention the scan lines in atleast one layer of at least a first three-dimensional article are fusedwith a first energy beam from a first energy beam source and at leastone layer of at least a second three-dimensional article is fused with asecond energy beam from a second energy beam source. More than oneenergy beam source may be used for fusing the scan lines. In anotherexample embodiment a first energy beam source may be used for scanningdirections within a first range of angles and a second energy beamsource may be used for scanning directions within a second range ofangles. The first end second ranges of angles may be overlapping ornon-overlapping with each other. The first and second energy beamsources may be used in sequence or simultaneously.

By using more than one energy beam source the build temperature of thethree-dimensional build may more easily be maintained compared to ifjust one beam source is used. The reason for this is that two beams maybe at more locations simultaneously than just one beam. Increasing thenumber of beam sources will further ease the control of the buildtemperature. By using a plurality of energy beam sources a first energybeam source may be used for melting the powder material and a secondenergy beam source may be used for heating the powder material in orderto keep the build temperature within a predetermined temperature range.

FIG. 6 illustrates schematically a view from above of athree-dimensional article 600 fused with a first energy beam 610 from afirst energy beam source (not shown) and a second energy beam 620 from asecond energy beam source (not shown). The three dimensional article 600has the same dimension as the three-dimensional article 100, 200 inFIGS. 1 and 2 respectively.

The first energy beam 610 is in FIG. 6 providing a scan line 606 in thebottom section of the three-dimensional article 600 having a width B₃and a length L. Already provided scan lines 601, 602, 603, 604, 605, inthe bottom section are separated with different distances. A first twoadjacent scan lines, made up by a first scan line 601 and a second scanline 602, are separated by a first distance D₃′″. A second two adjacentscan lines, made up by a second scan line 602 and a third scan line 603,are separated by a second distance D₃″. A third two adjacent scan lines,made up by a third scan line 603 and a fourth scan line 604, areseparated by a third distance D₃′. A fourth two adjacent scan lines,made up by a fourth scan line 604 and a fifth scan line 605, areseparated by a fourth distance D₃. In this example embodiment the firsttwo adjacent scan lines are provided before the second two adjacent scanlines which in turn is provided before the third two adjacent scan lineswhich in turn is provided before the fourth two adjacent scan lines. Thefirst distance D₃′″ is shorter than the second distance D₃″ which inturn is shorter than the third distance D₃′ which in turn is shorterthan the fourth distance D₃.

The second energy beam 620 is in FIG. 6 producing a scan line 625 in thetop section of the three-dimensional article 600 having a width B₁ and alength L. Already provided scan lines 621, 622, 623 and 624 in the topsection are separated with different distances. A first two adjacentscan lines, made up by a first scan line 621 and a second scan line 622,are separated by a first distance D₁″. A second two adjacent scan lines,made up by a second scan line 622 and a third scan line 623, areseparated by a second distance D₁′. A third two adjacent scan lines,made up by a third scan line 623 and a fourth scan line 624, areseparated by a third distance D₁. In this example embodiment the firsttwo adjacent scan lines are provided before the second two adjacent scanlines which in turn is provided before the third two adjacent scanlines. The first distance D₁″ is shorter than the second distance D₁′which in turn is shorter than the third distance D₁.

Two adjacent scan lines which are provided later than the fourth twoadjacent scan lines in the bottom section may be separated by the samedistance as the fourth two adjacent scan lines, i.e., after a number oftwo adjacent scan lines have been provided in a particular section theseparation distance between two adjacent scan lines may be constant. Inthe top section each two adjacent scan lines provided after the thirdtwo adjacent scan lines may be separated by the same distance.

By varying the separation distance between two adjacent scan lines onemay further control the energy deposited into a cross section andthereby further decrease the manufacturing time and/or improve thematerial characteristics at the beginning of the fusion of a crosssection. If using multiple energy beam sources, which may be of the sametype or of different types, a first distance between two adjacent scanlines provided by a first energy beam from a first energy beam source ata first part of the cross section may be varied simultaneously as afirst distance between two adjacent scan lines provided by a secondenergy beam from a second energy beam source at a second part of thecross section.

After a first layer is finished, i.e., the fusion of powder material formaking a first layer of the three-dimensional article, a second powderlayer is provided on the work table 316. The second powder layer ispreferably, as a non-limiting example, distributed according to the samemanner as the previous layer. However, there might be alternativemethods in the same additive manufacturing machine for distributingpowder onto the work table. For instance, a first layer may be providedby means of or via a first powder distributor, a second layer may beprovided by another powder distributor. The design of the powderdistributor is automatically changed according to instructions from thecontrol unit. A powder distributor in the form of a single rake system,i.e., where one rake is catching powder fallen down from both a leftpowder hopper 306 and a right powder hopper 307, the rake as such canchange design.

After having distributed the second powder layer on the work table 316,the energy beam from the energy beam source may be directed over thework table 316 causing the second powder layer to fuse in selectedlocation(s) according to the model to form second cross sections of thethree-dimensional article. Fused portions in the second layer may bebonded to fused portions of the first layer. The fused portions in thefirst and second layer may be melted together by melting not only thepowder in the uppermost layer but also remelting at least a fraction ofa thickness of a layer directly below the uppermost layer.

In another aspect of the invention it is provided a program elementconfigured and arranged when executed on a computer to implement amethod for forming at least one three-dimensional article throughsuccessive fusion of parts of a powder bed, which parts correspond tosuccessive cross sections of the three-dimensional article, the methodcomprising the steps of: providing a model of the at least onethree-dimensional article; applying a first powder layer on a worktable; directing a first energy beam from a first energy beam sourceover the work table so as to cause the first powder layer to fuse infirst selected locations according to corresponding models so as to forma first cross section of the three-dimensional article, where the firstenergy beam is configured to fuse at least a first region of a firstcross section with two or more parallel scan lines in a first direction;and determining a distance between two adjacent of the two or moreparallel scan lines, which are used for fusing the powder layer, as afunction of a length of at least one of the two adjacent scan lines. Theprogram element may be installed in a computer readable storage medium.The computer readable storage medium may be any control unit asdescribed elsewhere herein or another separate and distinct controlunit. The computer readable storage medium and the program element,which may comprise computer-readable program code portions embodiedtherein, may further be contained within a non-transitory computerprogram product. Further details regarding these features andconfigurations are provided, in turn, below.

As mentioned, various embodiments of the present invention may beimplemented in various ways, including as non-transitory computerprogram products. A computer program product may include anon-transitory computer-readable storage medium storing applications,programs, program modules, scripts, source code, program code, objectcode, byte code, compiled code, interpreted code, machine code,executable instructions, and/or the like (also referred to herein asexecutable instructions, instructions for execution, program code,and/or similar terms used herein interchangeably). Such non-transitorycomputer-readable storage media include all computer-readable media(including volatile and non-volatile media).

In one embodiment, a non-volatile computer-readable storage medium mayinclude a floppy disk, flexible disk, hard disk, solid-state storage(SSS) (e.g., a solid state drive (SSD), solid state card (SSC), solidstate module (SSM)), enterprise flash drive, magnetic tape, or any othernon-transitory magnetic medium, and/or the like. A non-volatilecomputer-readable storage medium may also include a punch card, papertape, optical mark sheet (or any other physical medium with patterns ofholes or other optically recognizable indicia), compact disc read onlymemory (CD-ROM), compact disc compact disc-rewritable (CD-RW), digitalversatile disc (DVD), Blu-ray disc (BD), any other non-transitoryoptical medium, and/or the like. Such a non-volatile computer-readablestorage medium may also include read-only memory (ROM), programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), flashmemory (e.g., Serial, NAND, NOR, and/or the like), multimedia memorycards (MMC), secure digital (SD) memory cards, SmartMedia cards,CompactFlash (CF) cards, Memory Sticks, and/or the like. Further, anon-volatile computer-readable storage medium may also includeconductive-bridging random access memory (CBRAM), phase-change randomaccess memory (PRAM), ferroelectric random-access memory (FeRAM),non-volatile random-access memory (NVRAM), magnetoresistiverandom-access memory (MRAM), resistive random-access memory (RRAM),Silicon-Oxide-Nitride-Oxide-Silicon memory (SONOS), floating junctiongate random access memory (FJG RAM), Millipede memory, racetrack memory,and/or the like.

In one embodiment, a volatile computer-readable storage medium mayinclude random access memory (RAM), dynamic random access memory (DRAM),static random access memory (SRAM), fast page mode dynamic random accessmemory (FPM DRAM), extended data-out dynamic random access memory (EDODRAM), synchronous dynamic random access memory (SDRAM), double datarate synchronous dynamic random access memory (DDR SDRAM), double datarate type two synchronous dynamic random access memory (DDR2 SDRAM),double data rate type three synchronous dynamic random access memory(DDR3 SDRAM), Rambus dynamic random access memory (RDRAM), TwinTransistor RAM (TTRAIVI), Thyristor RAM (T-RAM), Zero-capacitor (Z-RAM),Rambus in-line memory module (RIMM), dual in-line memory module (DIMM),single in-line memory module (SIMM), video random access memory VRAM,cache memory (including various levels), flash memory, register memory,and/or the like. It will be appreciated that where embodiments aredescribed to use a computer-readable storage medium, other types ofcomputer-readable storage media may be substituted for or used inaddition to the computer-readable storage media described above.

As should be appreciated, various embodiments of the present inventionmay also be implemented as methods, apparatus, systems, computingdevices, computing entities, and/or the like, as have been describedelsewhere herein. As such, embodiments of the present invention may takethe form of an apparatus, system, computing device, computing entity,and/or the like executing instructions stored on a computer-readablestorage medium to perform certain steps or operations. However,embodiments of the present invention may also take the form of anentirely hardware embodiment performing certain steps or operations.

Various embodiments are described below with reference to block diagramsand flowchart illustrations of apparatuses, methods, systems, andcomputer program products. It should be understood that each block ofany of the block diagrams and flowchart illustrations, respectively, maybe implemented in part by computer program instructions, e.g., aslogical steps or operations executing on a processor in a computingsystem. These computer program instructions may be loaded onto acomputer, such as a special purpose computer or other programmable dataprocessing apparatus to produce a specifically-configured machine, suchthat the instructions which execute on the computer or otherprogrammable data processing apparatus implement the functions specifiedin the flowchart block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including computer-readableinstructions for implementing the functionality specified in theflowchart block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed on the computeror other programmable apparatus to produce a computer-implementedprocess such that the instructions that execute on the computer or otherprogrammable apparatus provide operations for implementing the functionsspecified in the flowchart block or blocks.

Accordingly, blocks of the block diagrams and flowchart illustrationssupport various combinations for performing the specified functions,combinations of operations for performing the specified functions andprogram instructions for performing the specified functions. It shouldalso be understood that each block of the block diagrams and flowchartillustrations, and combinations of blocks in the block diagrams andflowchart illustrations, could be implemented by special purposehardware-based computer systems that perform the specified functions oroperations, or combinations of special purpose hardware and computerinstructions.

FIG. 7 is a block diagram of an exemplary system 1020 that can be usedin conjunction with various embodiments of the present invention. In atleast the illustrated embodiment, the system 1020 may include one ormore central computing devices 1110, one or more distributed computingdevices 1120, and one or more distributed handheld or mobile devices1300, all configured in communication with a central server 1200 (orcontrol unit) via one or more networks 1130. While FIG. 7 illustratesthe various system entities as separate, standalone entities, thevarious embodiments are not limited to this particular architecture.

According to various embodiments of the present invention, the one ormore networks 1130 may be capable of supporting communication inaccordance with any one or more of a number of second-generation (2G),2.5G, third-generation (3G), and/or fourth-generation (4G) mobilecommunication protocols, or the like. More particularly, the one or morenetworks 1130 may be capable of supporting communication in accordancewith 2G wireless communication protocols IS-136 (TDMA), GSM, and IS-95(CDMA). Also, for example, the one or more networks 1130 may be capableof supporting communication in accordance with 2.5G wirelesscommunication protocols GPRS, Enhanced Data GSM Environment (EDGE), orthe like. In addition, for example, the one or more networks 1130 may becapable of supporting communication in accordance with 3G wirelesscommunication protocols such as Universal Mobile Telephone System (UMTS)network employing Wideband Code Division Multiple Access (WCDMA) radioaccess technology. Some narrow-band AMPS (NAMPS), as well as TACS,network(s) may also benefit from embodiments of the present invention,as should dual or higher mode mobile stations (e.g., digital/analog orTDMA/CDMA/analog phones). As yet another example, each of the componentsof the system 1020 may be configured to communicate with one another inaccordance with techniques such as, for example, radio frequency (RF),Bluetooth™, infrared (IrDA), or any of a number of different wired orwireless networking techniques, including a wired or wireless PersonalArea Network (“PAN”), Local Area Network (“LAN”), Metropolitan AreaNetwork (“MAN”), Wide Area Network (“WAN”), or the like.

Although the device(s) 1110-1300 are illustrated in FIG. 7 ascommunicating with one another over the same network 1130, these devicesmay likewise communicate over multiple, separate networks.

According to one embodiment, in addition to receiving data from theserver 1200, the distributed devices 1110, 1120, and/or 1300 may befurther configured to collect and transmit data on their own. In variousembodiments, the devices 1110, 1120, and/or 1300 may be capable ofreceiving data via one or more input units or devices, such as a keypad,touchpad, barcode scanner, radio frequency identification (RFID) reader,interface card (e.g., modem, etc.) or receiver. The devices 1110, 1120,and/or 1300 may further be capable of storing data to one or morevolatile or non-volatile memory modules, and outputting the data via oneor more output units or devices, for example, by displaying data to theuser operating the device, or by transmitting data, for example over theone or more networks 1130.

In various embodiments, the server 1200 includes various systems forperforming one or more functions in accordance with various embodimentsof the present invention, including those more particularly shown anddescribed herein. It should be understood, however, that the server 1200might include a variety of alternative devices for performing one ormore like functions, without departing from the spirit and scope of thepresent invention. For example, at least a portion of the server 1200,in certain embodiments, may be located on the distributed device(s)1110, 1120, and/or the handheld or mobile device(s) 1300, as may bedesirable for particular applications. As will be described in furtherdetail below, in at least one embodiment, the handheld or mobiledevice(s) 1300 may contain one or more mobile applications 1330 whichmay be configured so as to provide a user interface for communicationwith the server 1200, all as will be likewise described in furtherdetail below.

FIG. 8A is a schematic diagram of the server 1200 according to variousembodiments. The server 1200 includes a processor 1230 that communicateswith other elements within the server via a system interface or bus1235. Also included in the server 1200 is a display/input device 1250for receiving and displaying data. This display/input device 1250 maybe, for example, a keyboard or pointing device that is used incombination with a monitor. The server 1200 further includes memory1220, which preferably includes both read only memory (ROM) 1226 andrandom access memory (RAM) 1222. The server's ROM 1226 is used to storea basic input/output system 1224 (BIOS), containing the basic routinesthat help to transfer information between elements within the server1200. Various ROM and RAM configurations have been previously describedherein.

In addition, the server 1200 includes at least one storage device orprogram storage 210, such as a hard disk drive, a floppy disk drive, aCD Rom drive, or optical disk drive, for storing information on variouscomputer-readable media, such as a hard disk, a removable magnetic disk,or a CD-ROM disk. As will be appreciated by one of ordinary skill in theart, each of these storage devices 1210 are connected to the system bus1235 by an appropriate interface. The storage devices 1210 and theirassociated computer-readable media provide nonvolatile storage for apersonal computer. As will be appreciated by one of ordinary skill inthe art, the computer-readable media described above could be replacedby any other type of computer-readable media known in the art. Suchmedia include, for example, magnetic cassettes, flash memory cards,digital video disks, and Bernoulli cartridges.

Although not shown, according to an embodiment, the storage device 1210and/or memory of the server 1200 may further provide the functions of adata storage device, which may store historical and/or current deliverydata and delivery conditions that may be accessed by the server 1200. Inthis regard, the storage device 1210 may comprise one or more databases.The term “database” refers to a structured collection of records or datathat is stored in a computer system, such as via a relational database,hierarchical database, or network database and as such, should not beconstrued in a limiting fashion.

A number of program modules (e.g., exemplary modules 1400-1700)comprising, for example, one or more computer-readable program codeportions executable by the processor 1230, may be stored by the variousstorage devices 1210 and within RAM 1222. Such program modules may alsoinclude an operating system 1280. In these and other embodiments, thevarious modules 1400, 1500, 1600, 1700 control certain aspects of theoperation of the server 1200 with the assistance of the processor 1230and operating system 1280. In still other embodiments, it should beunderstood that one or more additional and/or alternative modules mayalso be provided, without departing from the scope and nature of thepresent invention.

In various embodiments, the program modules 1400, 1500, 1600, 1700 areexecuted by the server 1200 and are configured to generate one or moregraphical user interfaces, reports, instructions, and/ornotifications/alerts, all accessible and/or transmittable to varioususers of the system 1020. In certain embodiments, the user interfaces,reports, instructions, and/or notifications/alerts may be accessible viaone or more networks 1130, which may include the Internet or otherfeasible communications network, as previously discussed.

In various embodiments, it should also be understood that one or more ofthe modules 1400, 1500, 1600, 1700 may be alternatively and/oradditionally (e.g., in duplicate) stored locally on one or more of thedevices 1110, 1120, and/or 1300 and may be executed by one or moreprocessors of the same. According to various embodiments, the modules1400, 1500, 1600, 1700 may send data to, receive data from, and utilizedata contained in one or more databases, which may be comprised of oneor more separate, linked and/or networked databases.

Also located within the server 1200 is a network interface 1260 forinterfacing and communicating with other elements of the one or morenetworks 1130. It will be appreciated by one of ordinary skill in theart that one or more of the server 1200 components may be locatedgeographically remotely from other server components. Furthermore, oneor more of the server 1200 components may be combined, and/or additionalcomponents performing functions described herein may also be included inthe server.

While the foregoing describes a single processor 1230, as one ofordinary skill in the art will recognize, the server 1200 may comprisemultiple processors operating in conjunction with one another to performthe functionality described herein. In addition to the memory 1220, theprocessor 1230 can also be connected to at least one interface or othermeans for displaying, transmitting and/or receiving data, content or thelike. In this regard, the interface(s) can include at least onecommunication interface or other means for transmitting and/or receivingdata, content or the like, as well as at least one user interface thatcan include a display and/or a user input interface, as will bedescribed in further detail below. The user input interface, in turn,can comprise any of a number of devices allowing the entity to receivedata from a user, such as a keypad, a touch display, a joystick or otherinput device.

Still further, while reference is made to the “server” 1200, as one ofordinary skill in the art will recognize, embodiments of the presentinvention are not limited to traditionally defined server architectures.Still further, the system of embodiments of the present invention is notlimited to a single server, or similar network entity or mainframecomputer system. Other similar architectures including one or morenetwork entities operating in conjunction with one another to providethe functionality described herein may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention. For example, a mesh network of two or more personal computers(PCs), similar electronic devices, or handheld portable devices,collaborating with one another to provide the functionality describedherein in association with the server 1200 may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention.

According to various embodiments, many individual steps of a process mayor may not be carried out utilizing the computer systems and/or serversdescribed herein, and the degree of computer implementation may vary, asmay be desirable and/or beneficial for one or more particularapplications.

FIG. 8B provides an illustrative schematic representative of a mobiledevice 1300 that can be used in conjunction with various embodiments ofthe present invention. Mobile devices 1300 can be operated by variousparties. As shown in FIG. 8B, a mobile device 1300 may include anantenna 1312, a transmitter 1304 (e.g., radio), a receiver 1306 (e.g.,radio), and a processing element 1308 that provides signals to andreceives signals from the transmitter 1304 and receiver 1306,respectively.

The signals provided to and received from the transmitter 1304 and thereceiver 1306, respectively, may include signaling data in accordancewith an air interface standard of applicable wireless systems tocommunicate with various entities, such as the server 1200, thedistributed devices 1110, 1120, and/or the like. In this regard, themobile device 1300 may be capable of operating with one or more airinterface standards, communication protocols, modulation types, andaccess types. More particularly, the mobile device 1300 may operate inaccordance with any of a number of wireless communication standards andprotocols. In a particular embodiment, the mobile device 1300 mayoperate in accordance with multiple wireless communication standards andprotocols, such as GPRS, UMTS, CDMA2000, 1×RTT, WCDMA, TD-SCDMA, LTE,E-UTRAN, EVDO, HSPA, HSDPA, Wi-Fi, WiMAX, UWB, IR protocols, Bluetoothprotocols, USB protocols, and/or any other wireless protocol.

Via these communication standards and protocols, the mobile device 1300may according to various embodiments communicate with various otherentities using concepts such as Unstructured Supplementary Service data(USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS),Dual-Tone Multi-Frequency Signaling (DTMF), and/or Subscriber IdentityModule Dialer (SIM dialer). The mobile device 1300 can also downloadchanges, add-ons, and updates, for instance, to its firmware, software(e.g., including executable instructions, applications, programmodules), and operating system.

According to one embodiment, the mobile device 1300 may include alocation determining device and/or functionality. For example, themobile device 1300 may include a GPS module adapted to acquire, forexample, latitude, longitude, altitude, geocode, course, and/or speeddata. In one embodiment, the GPS module acquires data, sometimes knownas ephemeris data, by identifying the number of satellites in view andthe relative positions of those satellites.

The mobile device 1300 may also comprise a user interface (that caninclude a display 1316 coupled to a processing element 1308) and/or auser input interface (coupled to a processing element 308). The userinput interface can comprise any of a number of devices allowing themobile device 1300 to receive data, such as a keypad 1318 (hard orsoft), a touch display, voice or motion interfaces, or other inputdevice. In embodiments including a keypad 1318, the keypad can include(or cause display of) the conventional numeric (0-9) and related keys(#, *), and other keys used for operating the mobile device 1300 and mayinclude a full set of alphabetic keys or set of keys that may beactivated to provide a full set of alphanumeric keys. In addition toproviding input, the user input interface can be used, for example, toactivate or deactivate certain functions, such as screen savers and/orsleep modes.

The mobile device 1300 can also include volatile storage or memory 1322and/or non-volatile storage or memory 1324, which can be embedded and/ormay be removable. For example, the non-volatile memory may be ROM, PROM,EPROM, EEPROM, flash memory, MMCs, SD memory cards, Memory Sticks,CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, and/or the like. Thevolatile memory may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDRSDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cachememory, register memory, and/or the like. The volatile and non-volatilestorage or memory can store databases, database instances, databasemapping systems, data, applications, programs, program modules, scripts,source code, object code, byte code, compiled code, interpreted code,machine code, executable instructions, and/or the like to implement thefunctions of the mobile device 1300.

The mobile device 1300 may also include one or more of a camera 1326 anda mobile application 1330. The camera 1326 may be configured accordingto various embodiments as an additional and/or alternative datacollection feature, whereby one or more items may be read, stored,and/or transmitted by the mobile device 1300 via the camera. The mobileapplication 1330 may further provide a feature via which various tasksmay be performed with the mobile device 1300. Various configurations maybe provided, as may be desirable for one or more users of the mobiledevice 1300 and the system 1020 as a whole.

The invention is not limited to the above-described embodiments and manymodifications are possible within the scope of the following claims.Such modifications may, for example, involve using a different source ofenergy beam than the exemplified electron beam such as a laser beam.Other materials than metallic powder may be used, such as thenon-limiting examples of: electrically conductive polymers and powder ofelectrically conductive ceramics.

That which is claimed:
 1. An apparatus for forming at least onethree-dimensional article through successive fusion of parts of a powderbed, which parts correspond to successive cross sections of thethree-dimensional article, said apparatus comprising: a control unithaving stored thereon a computer model of said at least onethree-dimensional article; and at least one energy beam from at leastone energy beam source, the at least one energy beam source being atleast one of an electron beam or a laser beam, wherein the control unitis configured to: determine a length of at least one of two adjacent oftwo or more parallel scan lines either applied to the first powder layeror to be applied to the first powder layer; set a distance between thetwo adjacent of two or more parallel scan lines as a function of thedetermined length, wherein the function of the determined length is suchthat as the determined length increases: (a) the distance increaseswhile the determined length is less than a predetermined value, and (b)the distance is a constant value while the determined length is equal toor greater than the predetermined value; and direct the at least oneenergy beam over said work table so as to cause said first powder layerto fuse in first selected locations according to a corresponding modelof said at least one three-dimensional article so as to form a firstcross section of said three-dimensional article, where the at least oneenergy beam is configured to fuse at least a first region of a firstcross section either with said two adjacent of said two or more parallelscan lines extending in a first direction and separated by said setdistance, or with at least one additional parallel scan line extendingin said first direction and separated from said two adjacent of said twoor more parallel scan lines by said set distance.
 2. The apparatus ofclaim 1, wherein said distance is also a function of the sequence ofsaid adjacent scan lines.
 3. The apparatus of claim 1, wherein: a firstset of two adjacent scan lines are separated with a first distance; asecond set of two adjacent scan lines, provided later than said firstset of adjacent scan lines, are separated with a second distance; andsaid first distance is smaller than said second distance.
 4. Theapparatus of claim 1, wherein said distance is determined based upon atleast one of: a function of the mean length of said two adjacent scanlines, a function of the longest of said two adjacent scan lines, or afunction of the shortest of said two adjacent scan lines.
 5. Theapparatus of claim 1, wherein said control unit is further configured tokeep at least one of a scan speed, an energy beam power, or an energybeam spot size on said powder layer constant for said two adjacent scanlines.
 6. The apparatus of claim 1, wherein said control unit is furtherconfigured to keep a time sink and a scan line time constant for eachscan line in at least one cross section of said three-dimensionalarticle.
 7. The apparatus of claim 1, wherein said distance between twoadjacent scan lines varies at least one of: linearly as a function of amean length of said two adjacent scan lines up to said predeterminedvalue, or as a function of the shortest scan line of said two adjacentscan lines up to said predetermined value.
 8. The apparatus of claim 1,wherein said energy beam is at least one of an electron beam or a laserbeam.
 9. The apparatus of claim 1, wherein the scan lines in at leastone layer of at least one three-dimensional article are straight lines.10. The apparatus of claim 1, wherein the scan lines in at least onelayer of at least one three-dimensional region are meandering lines. 11.The apparatus of claim 1, wherein: the at least one energy beamcomprises a first energy beam from a first energy beam source and asecond energy beam from a second energy beam source; and the adjacentscan lines in at least a first region are fused with the first energybeam and the second energy beam.
 12. The apparatus of claim 11, wherein:said first energy beam is emanating from a first electron beam source;and said second energy beam is emanating from a first laser beam source.13. The apparatus of claim 11, wherein: said first energy beam isemanating from a first electron beam source; and said second energy beamis emanating from a second electron beam source.
 14. The apparatus ofclaim 11, wherein: said first energy beam is emanating from a firstlaser beam source; and said second energy beam is emanating from asecond laser beam source.
 15. The apparatus of claim 11, wherein saidfirst and second energy beams are configured to fuse said adjacent scanlines simultaneously.
 16. The apparatus of claim 1, wherein: theadjacent scan lines in at least a first region are fused with a firstenergy beam from a first energy beam source and a second energy beamfrom a second energy beam source; said first energy beam is emanatingfrom at least one of a first electron beam source or a first laser beamsource; and said second energy beam is emanating from at least one of asecond electron beam source or a second laser beam source.
 17. Acomputer program product comprising at least one non-transitorycomputer-readable storage medium having computer-readable program codeportions embodied therein, the computer-readable program code portionscomprising one or more executable portions configured for: directingapplication of a first powder layer on a work table; determining alength of at least one of two adjacent of two or more parallel scanlines either applied to the first powder layer or to be applied to thefirst powder layer; setting a distance between the two adjacent of twoor more parallel scan lines as a function of the determined length,wherein the function of the determined length is such that as thedetermined length increases: (a) the distance increases while thedetermined length is less than a predetermined value, and (b) thedistance is a constant value while the determined length is equal to orgreater than the predetermined value; and directing a first energy beamfrom a first energy beam source over said work table so as to cause saidfirst powder layer to fuse in first selected locations according to acorresponding model of said at least one three-dimensional article so asto form a first cross section of said three-dimensional article, wheresaid first energy beam is configured to fuse at least a first region ofa first cross section either with said two adjacent of said two or moreparallel scan lines extending in a first direction and separated by saidset distance, or with at least one additional parallel scan lineextending in said first direction and separated from said two adjacentof said two or more parallel scan lines by said set distance.
 18. Thecomputer program product of claim 17, wherein said distance isdetermined based upon at least one of: a function of the mean length ofsaid two adjacent scan lines, a function of the longest of said twoadjacent scan lines, or a function of the shortest of said two adjacentscan lines.
 19. The computer program product of claim 17, furtherconfigured for keeping at least one of a scan speed, an energy beampower, or an energy beam spot size on said powder layer constant forsaid two adjacent scan lines.
 20. The computer program product of claim17, further configured for keeping a time sink and a scan line timeconstant for each scan line in at least one cross section of saidthree-dimensional article.